KB: Schematic Directives Do Not Appear in Constraint Manager
Updated: 十月 01, 2026
Altium Designer
Net classes, differential pair classes, differential pairs, and supported constraints can be defined in schematic source documents using directives. Customers may notice that these schematic-defined objects are not visible in Constraint Manager after opening the project. This behavior is expected because supported schematic directives are not automatically imported into Constraint Manager. A refresh and import operation is required to synchronize the schematic definitions. This article explains why the data is not visible, how to verify that the definitions are available for import, and how to import them into Constraint Manager.
Solution Details
Schematic Definitions Are Missing After Creation
After defining net classes, differential pair classes, differential pairs, or supported constraints in schematic source documents, those objects may not appear in Constraint Manager. As a result, users may be unable to find or manage the expected design data within the Constraint Manager interface.
Constraint Manager Requires Explicit Import
Definitions created in schematic source documents are not automatically transferred into Constraint Manager. A synchronization process is required to import supported classes, differential pairs, and constraints into Constraint Manager.
Steps to Synchronize Schematic Definitions
- Open Constraint Manager from the schematic side of the project.
- Click the Refresh button.
- Review the information displayed in the Refresh Constraint Manager dialog.
- Verify the summary of classes, differential pairs, and constraints that will be imported from the schematic documents.
- Click Import to complete the import process.
Supported Data Available for Import
- Import net classes defined in schematic directives.
- Import differential pair classes defined in schematic directives.
- Import differential pairs defined in schematic directives.
- Import constraints defined through supported schematic directives.
Additional Notes
- When using the Constraint Manager workflow, it is recommended to define and manage design data directly within Constraint Manager whenever possible. This includes net classes, differential pair classes, differential pairs, and associated constraints.
- Constraint Manager is available only for projects that were created with the Constraint Management option enabled. Projects using the legacy PCB Rules and Constraints Editor workflow do not use Constraint Manager unless they are migrated to the Constraint Manager approach.